Grouper (Epinephelus coioides) CXCR4 is expressed in response to pathogens infection and early stage of development.

Chemokine (C-X-C motif) receptor 4 (CXCR4) from orange-spotted grouper (Epinephelus coioides) was identified and characterized in this study. gCXCR4 shared common features in protein sequence and predicted structure of CXCR4 family. This suggested that gCXCR4 is a member of G protein-coupled receptors with seven transmembrane domains. The expression patterns revealed that gCXCR4 may play a key role in early development of grouper. Furthermore, overexpression of gCXCR4-GFP for 48 h had significant effects on the GF-1 cell viability. gCXCR4 protein was mainly expressed in the marginal zone of head kidney and on the surface of intestinal villi. gCXCR4 expression can be detected in all the examined tissues and significantly up-regulated in eye and brain, which are the main targets for nervous necrosis virus (NNV) infection and replication. gCXCR4 gene expression can be induced in the spleen and eye by lipopolysaccharide and NNV, respectively. Our data suggested that gCXCR4 may not only play a role in the early immune response to microbial infection but also restrain to the immune system and central nervous system.